The present invention relates to condensers, and more particularly to simulating performance of a condensing unit of an air-conditioning or refrigeration system.
Traditional cooling systems, such as refrigeration and air-conditioning systems, include a compressor, a condensing unit, an expansion valve and an evaporator. The compressor compresses gaseous refrigerant exiting the evaporator and discharges the high pressure refrigerant to the condensing unit. The condensing unit operates as a heat exchanger enabling heat transfer from the gaseous refrigerant to a heat sink (e.g. air or water). The refrigerant condenses within the condensing unit and a state change occurs from gas to liquid. The liquid refrigerant exits the condensing unit and flows to the evaporator through the expansion valve. The evaporator also operates as a heat exchanger enabling heat transfer from the atmosphere surrounding the evaporator to the liquid refrigerant. As the heat transfer occurs, the temperature of the refrigerant increases until a state change occurs from liquid to gas. The gas refrigerant is drawn into the suction side of the compressor and the cooling cycle continues.
The condensing unit can be one of an air-cooled condensing unit (ACU) or a water-cooled condensing unit (WCU). An ACU typically includes a fin-tube refrigerant-to-air heat exchanger, an air flow device such as a fan motor and fan blade and associated controls (not shown). In the case of an ACU, air provides the heat sink enabling heat transfer from the condensing unit. A WCU typically includes a refrigerant-to-water heat exchanger and associated controls (not shown). In the case of a WCU, water provides the heat sink enabling heat transfer from the condensing unit.
In order to competently design a new cooling system or maintain an existing cooling system, the potential performance of the individual components within the system need be estimated. Traditionally, system condensers are selected based on the refrigerant type and ratings provided by the manufacturer. However, these ratings are determined under fixed conditions and not actual system operational conditions. Therefore, although the rating of a condenser may suggest that it is proper for the particular cooling system, the actual performance of that condenser within the cooling system may be far less than optimal.
The present invention provides a method of determining thermal performance of a condensing unit within a cooling system. The method includes selecting the condensing unit from a condensing unit database and selecting a compressor from a compressor database based on a refrigerant flowing through the cooling system. Simulation points are determined and condensing unit characteristics and compressor characteristics are processed based on the simulation points to provide thermal performance data for the condensing unit.
In one feature, selecting the condensing unit from a condensing unit database further includes selecting a condenser, selecting a fan motor and selecting a fan blade.
In another feature, selecting the condensing unit is achieved by inputting part numbers of condensing unit components that are cross-referenced with the database.
In still another feature, determining the simulation points includes selecting an application type for an evaporator of the cooling system. The application type includes one of a low temperature range, a medium temperature range, an extended medium temperature range and a high temperature range.
In yet another feature, the method further includes outputting the thermal performance data in one of a graphical format, a spreadsheet format and a tabulated format. The thermal performance data includes condensing unit capacity across each of the simulation points for a given ambient temperature at which the condensing unit operates.
In still another feature, the method further includes scaling the thermal performance data based on compressor frequency.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.